Viscosity and the phenomenon of percolation in microemulsions

Peyrelasse, J.; Moha-Ouchane, M.; Boned, Christian

doi:10.1103/physreva.38.4155

Cited by 57 publications

(39 citation statements)

References 28 publications

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“…The o s η behaviour in dilute and semidilute regime resembles that already seen in other C i E j solutions 5,10,13,14 and microemulsions 15,16,17 . In the latter it was interpreted on the ground of percolation processes and, in analogy, we tried to describe our data according to the scaling relations of the asymptotic behaviour of o At high concentration (from 65 to 100 wt%) the viscosity exhibits a different trend, i.e.…”

Section: A Viscositysupporting

confidence: 79%

Shear and Longitudinal Viscosity of Non-ionic C₁₂E₈ Aqueous Solutions

D’Arrigo¹,

Briganti²,

Maccarini³

2006

J. Phys. Chem. B

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We present an extensive set of measurements of steady shear viscosity (η°s), longitudinal elastic modulus (M') and ultrasonic absorption (α) in the one-phase isotropic liquid region of the nonionic surfactant C 12 E 8 aqueous solutions. Within a given temperature interval, this phase extends along the entire surfactant concentration range, that could be fully covered in the experiments. In agreement with previous studies, the overall results support the presence of two separated intervals of concentration corresponding to different structural properties. In the surfactant-rich region the temperature dependence of η°s follows an equation characteristic of glass-like systems. The ultrasonic absorption spectra show unambiguous evidence of viscoelastic behaviour that can be described by a ColeCole relaxation formula. In this region, when both the absorption and the frequency are scaled by the static shear viscosity (η°s), the scaled attenuation reduces to a single universal curve for all temperatures and concentrations. In the water-rich region the behaviour of η°s, M' and α are more complex and reflect the presence of dispersed aggregates whose size increases with temperature and concentration. At these concentrations the ultrasonic spectra are characterized by a multiple decay rate. The high frequency tail falls in the same frequency range seen at high surfactant content and exhibits similar behaviors. This contribution is ascribed to the mixture of hydrophilic terminations and water present at the micellar interfaces that resembles the condition of a concentrated polymer solution. An additional low frequency contribution is also observed, which is ascribed to the exchange of water molecules and/or surfactant monomers between the aggregates and the bulk solvent region.

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Section: A Viscositysupporting

confidence: 79%

Shear and Longitudinal Viscosity of Non-ionic C₁₂E₈ Aqueous Solutions

D’Arrigo¹,

Briganti²,

Maccarini³

2006

J. Phys. Chem. B

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“…The densities of the AOT/isooctane reverse micelles and the AOT/ water/isooctane microemulsions with R being 2, 8,10,12,16,18,20,25,30, and 40 were measured for various concentrations at 303.15 K and are listed in Tables S1 and S2 of the Supporting Information, respectively. Among these systems the density measurements of AOT/ isooctane reverse micelles and AOT/water/isooctane microemulsions with R being 20 were carried out in very low concentrations of the solute to explore the instability condition of the reverse micelles and the microemulsions.…”

Section: Methodsmentioning

confidence: 99%

“…In this paper, the micelle and microemulsions with AOT being the surfactant and isooctane being the oil and the molar ratios R being 2, 8,10,12,16,18,20,25,30, and 40 were investigated by density measurements at 303.15 K. We choose AOT as the surfactant in this study not only for its wide practical applications 20−23 but also for the large amount of information about it accumulated in the previous extensive studies. 24−27 The apparent specific volumes of AOT in the reverse micelle and the quasi-component water/AOT in the microemulsions with different R at various concentrations are deduced from the density data and used to examine the volumetric properties of the surfactant and water both in the droplets and in the continuous phase, to discuss the droplet interaction, and to determine the critical micelle or microemulsion concentrations.…”

Section: Introductionmentioning

confidence: 99%

Volumetric Properties of Water/AOT/Isooctane Microemulsions

Yin

2014

Langmuir

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The densities of AOT/isooctane micelles and water/AOT/isooctane microemulsions with the molar ratios R of water to AOT being 2, 8, 10, 12, 16, 18, 20, 25, 30, and 40 were measured at 303.15 K. The apparent specific volumes of AOT and the quasi-component water/AOT at various concentrations were calculated and used to estimate the volumetric properties of AOT and water in the droplets and in the continuous oil phase, to discuss the interaction between the droplets, and to determine the critical micelle concentration and the critical microemulsion concentrations. A thermodynamic model was proposed to analysis the stability boundary of the microemulsion droplets, which confirms the maximum value of R being about 65 for the stable AOT/water/isooctane microemulsion droplets.

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“…The global viscosity maxima at R= 0.3 coincides with the formation of a bicontinuous microstructure, characterized by sample spanning, interpenetrating oil and water channels. In the past, both shear thinning (Saidi et al, 1990) and Newtonian flow behavior (Blom & Mellema, 1988;Peyerlasse et al, 1988;Saidi et al, 1990) was observed for bicontinuous structures at R = 0.3-0.5. However, most reports point to a Newtonian behaviour indicating that there could be occurrence of different microstructures other than bicontinuous for the R values indicated above.…”

Section: Viscosity Changes Across the 1- Channel At 28 ºCmentioning

confidence: 99%